/*
 * C/C++ Lessons Program
 * 
 * Copyright (c) 2012 Ken Zhang (cpp.china@gmail.com)
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this program; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place, Suite 330,
 * Boston, MA  02111-1307  USA
 *
 */


#include <stdio.h>

int main()
{
	FILE *stream = fopen("ungetc.c", "r");
	if (stream == NULL) {
		perror("Failed to open ungetc.c");
		return -1;
	}

	/* First, unget 10000 ESCs to the stream */
	int c, i = 0, j;
	do {
		c = ungetc(0x1B, stream);
		printf("<%d> ungetc returns %d.\n", ++i, c);
	} while (i < 10000);

	i = j = 0;

	/* Then, read all content out of the stream */
	while (!feof(stream)) {
		c = fgetc(stream);
		if (feof(stream)) {
			break;
		}
		else {
			++i;
			putchar(c);
			if (c == 0x1B) j++;
		}
	}

	/* Result */
	/* The man page states only one push back is guaranteed */
	/* But the result shows 10000 times of call is still Ok */
	printf("Total read: %d, count of ESC: %d\n", i, j);

	return 0;
}

